iPhoto error, "no photos to import" when trying to import from S4 to Macbook Air

I have downloaded Android file transfer. But when I copy the DCIM folder which contains the Camera folder onto my desktop, there are no photos in the Camera folder; the folder is empty (connected as MTP). Also, when I switch from Connected as a Media Device (MTP) to Camera (PTP) on my phone, iPhoto says that there are no photos to import. The photos are on my phone, and I know that they are in the DCIM folder, but my Macbook is not recognizing them. Help! I'm running out of memory on my phone, pictures have not been auto-backed up to Google for months, and now I can't even transfer to my computer.